This is a project designed to correlate the clinical course (and serum levels of carcinoembryonic antigen) with steroid sulfokinase and estrogen binding activities in normal and neoplastic human breast tissue. The patient population will be drawn from our own Surgical Oncology Service (MCV/VCU), as well as local cooperating hospitals, and will include patients now being or previously treated for primary or metastatic breast cancer. The specific assay procedure currently being used in our laboratory for measuring sulfokinase activity on these tissues will be examined with the goal of improving its clinical usefulness as a predictor of clinical course or response to therapy. The steroid specific enzyme catalyzed reactions that comprise the enzyme system for steroid conjugation will be measured along with nuclear and cytoplasmic estrogen binding activity on the normal and neoplastic tissues from the same patients. By simultaneous measurement of these biochemical parameters, we hope to clarify their general metabolic role and their usefulness in predicting clinical course and potential success of endocrine ablation therapy. Serial measurement of carcinoembryonic antigen (CEA) will also be correlated with clinical course of the patients in this study.